#4个数字【1，2，3，4】选出三个互不相同的数字组成一个三位数

def three(arr):
    list = []
    for i in range(len(arr)):
        for j in range(len(arr)):
            for m in range(len(arr)):
                if i == j or j == m or i == m:
                    continue
                num = arr[i]*100+arr[j]*10+arr[m]
                list.append(num)
    return list,len(list)
print(three([1,2,3,4]))
